I like the form factor:  plenty of folks use them without many external peripherals, and/or in use cases where there's a benefit to the small dimensions, some folks like myself aren't really that concerned the with size (you know, within reason ...) and like having external components that are easily arranged/stored/placed independently of the "core" machine.  Cables/workspaces are easily managed, you've got some minimum cable needs (power/display) and if you're really into the most cable-free aesthetic, you're probably a candidate for an AIO.
I mean, I'm pretty neat with my desk, but I've got two displays (and their cables), a USB device or two, audio out to a little tube amp (wired HD650s).  Two little boxes for the machine + eGPU isn't much different than one bigger box in terms of my overall 
cable-ness